Superconducting Single-Photon Spectrometer with 3D-Printed Photonic-Crystal Filters

Single-photon spectrometers utilizing optical spectral components and single-photon detectors have shown exceptional spectral resolving capability with single-photon sensitivity, enabling numerous spectroscopy applications in photon scarce environments. Here, we report a compact computational spectrometer combining a superconducting single-photon detector array and 3D-printed photonic-crystal filters. The unknown light source is encoded by passing through the 3D-printed filters with various spectral transmissions, detected by a broadband superconducting single-photon detector array, and finally computationally reconstructed using the known spectral features of each array element. The fabricated spectrometer shows system sensitivity down to powers of -108.2 dBm at 1310 nm and achieves a resolution of 5 nm ranging from 1200 to 1700 nm.